Ratcheting screwdrivers are already known in the prior art. These ratcheting screwdrivers or mechanisms are known and utilized for the performance of ratcheting in either direction or not ratcheting at all. In that prior art, and in context of the present invention, the ratcheting mechanism utilizes a gear which carries the screwdriver or tool bit, and also utilizes two pawls which are moved into and out of driving relationship with the gear.
Examples of ratcheting mechanisms which utilize two pawls which are fully movable toward and away from the driven gear are seen in U.S. Pat. Nos. 878,657 and 1,388,836 and 1,388,923 and 2,193,984. As mentioned, in those examples, the pawls are totally moved toward and away from the gear, and conventional type compression springs are positioned behind the pawls for urging them into toothed relationship with the gear. Also, an actuating mechanism, such as an intervening pin, is disposed between the pawls for moving the pawls against the backup springs and away from the gear for the selectivity of the ratcheting mode desired.
Also, the prior art is aware of ratchet mechanisms which utilize pawls that generally employ a pivotal action in moving the pawl teeth into and out of engagement with the gear teeth. Examples of that are seen in U.S. Pat. Nos. 791,895 and 3,356,117 and 3,742,787 and 4,466,523.
In multiple embodiments in the present invention, the concept of the total displacement and the pivotal action of the pawls is employed. However, in the present invention, the ratcheting mechanism is structurally simplified and is more reliable and sturdy. Also, U.S. Pat. No. 4,777,852 shows a ratcheting screwdriver which employs at least one part in addition to the total number of parts employed in the present invention, and thus the present invention is an improvement and is simplified and more reliable.
Also, the present invention improves upon the prior art in that it is easier to construct and assemble, and it is less expensive. Further, once the present invention's construction is positioned in an operating mode mentioned, it is more reliable in remaining in that mode and less likely that it can be operated or accidentally moved out of the desired mode, as well as being intentionally but undesirably moved from the desired mode. In the present invention, the direct and simple and easy finger maneuvering of one part of the mechanism will directly impart its motion onto the pawls for positioning the pawls in any one of the three desired modes mentioned. That is, there is no multiplicity of actuating parts, and the pawls are moved directly and are retained in the selected position until the operator desires to reestablish the mode by moving the pawls to a different position. Also, the movement of the actuator in the present invention is accomplished in one direction which is the same direction in which the ratcheting action is achieved, rather than a reverse direction which tends to obscure the operation or confuse the user.
Also, in the present invention, the pawls are definitely and firmly positioned in either position of engagement or disengagement relative to the driven gear which carries the work tool, such as a screwdriver bit. This again is achieved by the requirement for only a minimum number of parts which are reliable and adequately positionable and are retained in their position without being susceptible to dislodging or repositioning to where they are not desired.
With ratcheting, it is important that one's hand remain in secure gripping of the tool's handle. A high friction and elastomer handle cover provides the optimum grip, and yet is capable of being repeatedly autoclavable for sterilization, without physical deterioration. Such is the silicone rubber cover. The handle material and surface differ from that in U.S. Pat. Nos. 3,340,914 and 3,438,413.